Migration Characteristics of Boring Mud in Roadway Floor Anchor Wire Hole and Test in Coal Mine

Hui Zhang,Weihai Han,Youlin Xu,Zhenfeng Wang,Zhanyang Liu,Mengzhi Zhu,Shazim Memon

doi:10.1155/2021/8817498

Abstract

Given the difficulty in drilling the anchor holes in the roadway floor of the coal mine, the characteristics of slag movement in the process of positive and negative circulation drilling are analyzed. It is concluded that the interaction between the three zones of drilling and slag is the fundamental reason restricting the rapid drilling of the anchor cable hole in the floor, and it is proposed that the pump reverse circulation drilling can effectively prevent the formation of the three zones of drilling and slag. According to the actual situation, the relationship between drilling depth, vacuum degree of the pump, and the velocity of drilling fluid and the volume of drilling slag is obtained. The results show that the pump suction reverse circulation is feasible for the rapid drilling of the anchor hole of the floor. A set of pump suction reverse circulation drilling systems has been developed, and floor anchor wire hole drilling and slag discharge operation at the same time were realized. The field test shows that the effective drilling time of the anchor cable hole in the depth of 5.6 m can be controlled within 30 min, which solves the problem of deep hole drilling in the anchor hole of the bottom plate and purifies the working environment.

Highlights

Bit drilling zoneTo a large extent, avoiding the interaction between drilling and slag, three areas are the key to speeding up drilling speed
E pressure supply equipment needs to be increased but the hole wall is seriously damaged and the working environment of the roadway deteriorates
Due to the limitations of drilling tools, it is difficult for workers to predict the formation of drilling and gathering areas due to the operation of machines and tools, resulting in extremely slow drilling speed of floor anchor holes, which cannot meet the needs of the development of roadway floor anchoring technology

Summary

Bit drilling zone

To a large extent, avoiding the interaction between drilling and slag, three areas are the key to speeding up drilling speed. Due to the limitations of drilling tools, it is difficult for workers to predict the formation of drilling and gathering areas due to the operation of machines and tools, resulting in extremely slow drilling speed of floor anchor holes, which cannot meet the needs of the development of roadway floor anchoring technology. Characteristic Analysis of Pumping Reverse Circulation Slag Discharging for Anchor Cable Hole. In the reverse circulation drilling, the high-pressure pump is used to send the washing liquid through the drill pipe to the bottom of the hole, and the flushing fluid is discharged from the pores between the drill pipe and the hole wall, resulting in the deterioration of the working environment of the roadway floor.

Slag drilling

Findings

Conclusion